log3(2)=1/alog3(7)=b log84(112)=log3(112)/log3(84)（换底公式）=[log3(7)+4log3(2)]/(log3(3)+log3(7)+2log3(2))=(4/a+b)/(1+b+2/a)=(4+ab)/(a+ab+2)如果帮到你,请记得采纳,O(...